Identification of Groundwater Potential Zones Using AHP, GIS and RS Integration: A Case Study of Didessa Sub-Basin, Western Ethiopia

Abstract

Groundwater is a precious water resource in underground rocks and major water source for drinking, industry and irrigation. Identifying the groundwater potential zones in certain areas of Ethiopia is still challenging in terms of time and cost for resolving water scarcity. Groundwater evaluations in Ethiopia are normally done based on field survey. Therefore, this study aims to use the timely and cost-effective remote sensing data and GIS techniques for the evaluation of groundwater potentials in Didessa Sub-Basin from Western Ethiopia. STRM DEM and Landsat-8 satellite image with secondary data was used for this study. Thematic layers showing distribution of slope, lithology, lineament density, drainage density, LULC, soil texture and rainfall were analyzed using weight overlay analysis and AHP algorithm to determine the groundwater potentials. The weights for each element then assigned according to their relative relevance using Saaty’s (AHP) scale. The rainfall and geomorphology showed a higher weight and lithology the lowest. About 4.6% (1289.4km2) of the study area was classified as ‘very high potential, 66% (18532.2 km2) classified as ‘high potential, 27% (7683km2) as moderate potential and 2.1% (587.5 km2) as ‘low’ groundwater potential areas. Therefore, this study demonstrates a robust method, efficient and useful technique for delineating and mapping groundwater potential zones for planning and decision-making for better groundwater management.